When logging an inode in full mode that has an inline compressed extent
that represents a range with a size matching the sector size (currently
the same as the page size), has a trailing hole and the no-holes feature
is enabled, we end up failing an assertion leading to a trace like the
following:

[141812.031528] assertion failed: len == i_size, file: fs/btrfs/tree-log.c, line: 4453
[141812.033069] ------------[ cut here ]------------
[141812.034330] kernel BUG at fs/btrfs/ctree.h:3452!
[141812.035137] invalid opcode: 0000 [#1] PREEMPT SMP
[141812.035932] Modules linked in: btrfs dm_thin_pool dm_persistent_data dm_bio_prison dm_bufio dm_flakey dm_mod dax ppdev evdev ghash_clmulni_intel pcbc aesni_intel aes_x86_64 tpm_tis psmouse crypto_simd parport_pc sg pcspkr tpm_tis_core cryptd parport serio_raw glue_helper tpm i2c_piix4 i2c_core button sunrpc loop autofs4 ext4 crc16 jbd2 mbcache raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath linear md_mod sd_mod ata_generic virtio_scsi ata_piix floppy crc32c_intel libata scsi_mod virtio_pci virtio_ring e1000 virtio [last unloaded: btrfs]
[141812.036790] CPU: 3 PID: 845 Comm: fdm-stress Tainted: G    B   W       4.12.3-btrfs-next-52+ #1
[141812.036790] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014
[141812.036790] task: ffff8801e6694180 task.stack: ffffc90009004000
[141812.036790] RIP: 0010:assfail.constprop.18+0x1c/0x1e [btrfs]
[141812.036790] RSP: 0018:ffffc90009007bc0 EFLAGS: 00010282
[141812.036790] RAX: 0000000000000046 RBX: ffff88017512c008 RCX: 0000000000000001
[141812.036790] RDX: ffff88023fd95201 RSI: ffffffff8182264c RDI: 00000000ffffffff
[141812.036790] RBP: ffffc90009007bc0 R08: 0000000000000001 R09: 0000000000000001
[141812.036790] R10: 0000000000001000 R11: ffffffff82f5a0c9 R12: ffff88014e5947e8
[141812.036790] R13: 00000000000b4000 R14: ffff8801b234d008 R15: 0000000000000000
[141812.036790] FS:  00007fdba6ffd700(0000) GS:ffff88023fd80000(0000) knlGS:0000000000000000
[141812.036790] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[141812.036790] CR2: 00007fdb9c000010 CR3: 000000016efa2000 CR4: 00000000001406e0
[141812.036790] Call Trace:
[141812.036790]  btrfs_log_inode+0x9f0/0xd3d [btrfs]
[141812.036790]  ? __mutex_lock+0x120/0x3ce
[141812.036790]  btrfs_log_inode_parent+0x224/0x685 [btrfs]
[141812.036790]  ? lock_acquire+0x16b/0x1af
[141812.036790]  btrfs_log_dentry_safe+0x60/0x7b [btrfs]
[141812.036790]  btrfs_sync_file+0x32e/0x3f8 [btrfs]
[141812.036790]  vfs_fsync_range+0x8a/0x9d
[141812.036790]  vfs_fsync+0x1c/0x1e
[141812.036790]  do_fsync+0x31/0x4a
[141812.036790]  SyS_fdatasync+0x13/0x17
[141812.036790]  entry_SYSCALL_64_fastpath+0x18/0xad
[141812.036790] RIP: 0033:0x7fdbac41a47d
[141812.036790] RSP: 002b:00007fdba6ffce30 EFLAGS: 00000293 ORIG_RAX: 000000000000004b
[141812.036790] RAX: ffffffffffffffda RBX: ffffffff81092c9f RCX: 00007fdbac41a47d
[141812.036790] RDX: 0000004cf0160a40 RSI: 0000000000000000 RDI: 0000000000000006
[141812.036790] RBP: ffffc90009007f98 R08: 0000000000000000 R09: 0000000000000010
[141812.036790] R10: 00000000000002e8 R11: 0000000000000293 R12: ffffffff8110cd90
[141812.036790] R13: ffffc90009007f78 R14: 0000000000000000 R15: 0000000000000000
[141812.036790]  ? time_hardirqs_off+0x9/0x14
[141812.036790]  ? trace_hardirqs_off_caller+0x1f/0xa3
[141812.036790] Code: c7 d6 61 6b a0 48 89 e5 e8 ba ef a8 e0 0f 0b 55 89 f1 48 c7 c2 6d 65 6b a0 48 89 fe 48 c7 c7 81 65 6b a0 48 89 e5 e8 9c ef a8 e0 <0f> 0b 0f 1f 44 00 00 55 48 89 e5 41 57 41 56 41 55 41 54 49 89
[141812.036790] RIP: assfail.constprop.18+0x1c/0x1e [btrfs] RSP: ffffc90009007bc0
[141812.084448] ---[ end trace 44e472684c7a32cc ]---

Which happens because the code that logs a trailing hole when the no-holes
feature is enabled, did not consider that a compressed inline extent can
represent a range with a size matching the sector size, in which case
expanding the inode's i_size, through a truncate operation, won't lead
to padding with zeroes the page that represents the inline extent, and
therefore the inline extent remains after the truncation.

Fix this by adapting the assertion to accept inline extents representing
data with a sector size length if, and only if, the inline extents are
compressed.

A sample and trivial reproducer (for systems with a 4K page size) for this
issue:

  mkfs.btrfs -O no-holes -f /dev/sdc
  mount -o compress /dev/sdc /mnt
  xfs_io -f -c "pwrite -S 0xab 0 4K" /mnt/foobar
  sync
  xfs_io -c "truncate 32K" /mnt/foobar
  xfs_io -c "fsync" /mnt/foobar
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>

If the range being cleared was not marked for defrag and we are not
about to clear the range from the defrag status, we don't need to
lock and unlock the inode.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Chris Mason <clm@fb.com>
Reviewed-by: Wang Shilong <wangshilong1991@gmail.com>
Signed-off-by: Chris Mason <clm@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>

The error return variable ret is initialized to zero and then is
checked to see if it is non-zero in the if-block that follows it.
It is therefore impossible for ret to be non-zero after the if-block
hence the check is redundant and can be removed.

Detected by CoverityScan, CID#1021040 ("Logically dead code")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

The internal free space tree management routines are always exposed for
testing purposes. Make them dependent on SANITY_TESTS being on so that
they are exposed only when they really have to.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

This variable was added in 1abe9b8a ("Btrfs: add initial tracepointi
support for btrfs"), yet it never really got used, only assigned to. So
let's remove it.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

We have a WARN_ON(!var) inside an if branch which is executed (among
others) only when var is true.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

We aren't using this define, so removing it.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

We have define for FSID size so use it.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Though BTRFS_FSID_SIZE and BTRFS_UUID_SIZE are of the same size, we
should use the matching constant for the fsid buffer.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Our dir_context->pos is supposed to hold the next position we're
supposed to look.  If we successfully insert a delayed dir index we
could end up with a duplicate entry because we don't increase ctx->pos
after doing the dir_emit.
Signed-off-by: Josef Bacik <jbacik@fb.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Readdir does dir_emit while under the btree lock.  dir_emit can trigger
the page fault which means we can deadlock.  Fix this by allocating a
buffer on opening a directory and copying the readdir into this buffer
and doing dir_emit from outside of the tree lock.

Thread A
readdir  <holding tree lock>
  dir_emit
    <page fault>
      down_read(mmap_sem)

Thread B
mmap write
  down_write(mmap_sem)
    page_mkwrite
      wait_ordered_extents

Process C
finish_ordered_extent
  insert_reserved_file_extent
   try to lock leaf <hang>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ copy the deadlock scenario to changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>

Currently should_alloc_chunk uses ->total_bytes - ->bytes_readonly to
signify the total amount of bytes in this space info. However, given
Jeff's patch which adds bytes_pinned and bytes_may_use to the calculation
of num_allocated it becomes a lot more clear to just eliminate num_bytes
altogether and add the bytes_readonly to the amount of used space. That
way we don't change the results of the following statements. In the
process also start using btrfs_space_info_used.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

In a heavy write scenario, we can end up with a large number of pinned bytes.
This can translate into (very) premature ENOSPC because pinned bytes
must be accounted for when allowing a reservation but aren't accounted for
when deciding whether to create a new chunk.

This patch adds the accounting to should_alloc_chunk so that we can
create the chunk.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

This is a minimal patch intended to be backported to older kernels.
We're going to extend the string specifying the compression method and
this would fail on kernels before that change (the string is compared
exactly).

Relax the string matching only to the prefix, ie. ignoring anything that
goes after "zlib" or "lzo", regardless of th format extension we decide
to use. This applies to the mount options and properties.

That way, patched old kernels could be booted on systems already
utilizing the new compression spec.

Applicable since commit 63541927, v3.14.
Signed-off-by: David Sterba <dsterba@suse.com>

Currently, the BTRFS_INODE_NOCOMPRESS will prevent any compression on a
given file, except when the mount is force-compress. As users have
reported on IRC, this will also prevent compression when requested by
defrag (btrfs fi defrag -c file).

The nocompress flag is set automatically by filesystem when the ratios
are bad and the user would have to manually drop the bit in order to
make defrag -c work. This is not good from the usability perspective.

This patch will raise priority for the defrag -c over nocompress, ie.
any file with NOCOMPRESS bit set will get defragmented. The bit will
remain untouched.

Alternate option was to also drop the nocompress bit and keep the
decision logic as is, but I think this is not the right solution.
Signed-off-by: David Sterba <dsterba@suse.com>

Signed-off-by: David Sterba <dsterba@suse.com>

Add new value for compression to distinguish between defrag and
property. Previously, a single variable was used and this caused clashes
when the per-file 'compression' was set and a defrag -c was called.

The property-compression is loaded when the file is open, defrag will
overwrite the same variable and reset to 0 (ie. NONE) at when the file
defragmentaion is finished. That's considered a usability bug.

Now we won't touch the property value, use the defrag-compression. The
precedence of defrag is higher than for property (and whole-filesystem).
Signed-off-by: David Sterba <dsterba@suse.com>

This is preparatory for separating inode compression requested by defrag
and set via properties. This will fix a usability bug when defrag will
reset compression type to NONE. If the file has compression set via
property, it will not apply anymore (until next mount or reset through
command line).

We're going to fix that by adding another variable just for the defrag
call and won't touch the property. The defrag will have higher priority
when deciding whether to compress the data.
Signed-off-by: David Sterba <dsterba@suse.com>

Add skeleton code for compresison heuristics. Now it iterates over all
the pages, but in the end always says "yes, compress please", ie it does
not change the current behaviour.

In the future we're going to add various heuristics to analyze the data.
This patch can be used as a baseline for measuring if the effectivness
and performance.
Signed-off-by: Timofey Titovets <nefelim4ag@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ enhanced changelog, modified comments ]
Signed-off-by: David Sterba <dsterba@suse.com>

Correctly account for IO when waiting for a submitted bio in scrub. This
only for the accounting purposes and should not change other behaviour.
Signed-off-by: David Sterba <dsterba@suse.com>

Correctly account for IO when waiting for a submitted DIO read, the case
when we're retrying.  This only for the accounting purposes and should
not change other behaviour.
Signed-off-by: David Sterba <dsterba@suse.com>

The pinned chunks might be left over so we clean them but at this point
of close_ctree, there's noone to race with, the locking can be removed.
Signed-off-by: David Sterba <dsterba@suse.com>

It's a simple call page_cache_sync_readahead, same arguments in the same
order.
Signed-off-by: David Sterba <dsterba@suse.com>

There's no PageFsMisc. Added by patch 4881ee5a in 2008, the flag is
not present in current kernels.
Signed-off-by: David Sterba <dsterba@suse.com>

Signed-off-by: David Sterba <dsterba@suse.com>

The return value of flush_space was used to have significance in the
early days when the code was first introduced and before the ticketed
enospc rework. Since the latter got introduced the return value lost any
significance whatsoever to its callers. So let's remove it. While at it
also remove the unused ticket variable in
btrfs_async_reclaim_metadata_space. It was used in the initial version
of the ticketed ENOSPC work, however Wang Xiaoguang detected a problem
with this and fixed it in ce129655 ("btrfs: introduce tickets_id to
determine whether asynchronous metadata reclaim work makes progress").
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ add comment ]
Signed-off-by: David Sterba <dsterba@suse.com>

Userspace transactions were introduced in commit 6bf13c0c ("Btrfs:
transaction ioctls") to provide semantics that Ceph's object store
required. However, things have changed significantly since then, to the
point where btrfs is no longer suitable as a backend for ceph and in
fact it's actively advised against such usages. Considering this, there
doesn't seem to be a widespread, legit use case of userspace
transaction. They also clutter the file->private pointer.

So to end the agony let's nuke the userspace transaction ioctls. As a
first step let's give time for people to voice their objection by just
WARN()ining when the userspace transaction is used.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ move the warning past perm checks, keep the has-been-printed state;
  we're ok with just one warning over all filesystems ]
Signed-off-by: David Sterba <dsterba@suse.com>

Superblock is read and written using buffer heads, we need to set the
bdev blocksize. The magic constant has been hardcoded in several places,
so replace it with a named constant.
Signed-off-by: David Sterba <dsterba@suse.com>

There are two independent parts, one that writes the superblocks and
another that waits for completion. No functional changes, but cleanups,
reformatting and comment updates.
Signed-off-by: David Sterba <dsterba@suse.com>

Polish the helper:
* drop underscores, no special meaning here
* pass fs_devices, as this is what the API implements
* drop noinline, no apparent reason for such simple helper
* constify uuid
* add comment
Signed-off-by: David Sterba <dsterba@suse.com>

There are two helpers called in chain from one location, we can merge the
functionaliy.

Originally, alloc_fs_devices could fill the device uuid randomly if we
we didn't give the uuid buffer. This happens for seed devices but the
fsid is generated in btrfs_prepare_sprout, so we can remove it.
Signed-off-by: David Sterba <dsterba@suse.com>

The function submit_extent_page has 15(!) parameters right now, op and
op_flags are effectively one value stored to bio::bi_opf, no need to
pass them separately. So it's 14 parameters now.
Signed-off-by: David Sterba <dsterba@suse.com>

Unify types of local variables and parameters that store various
REQ_* values to unsigned int.
Signed-off-by: David Sterba <dsterba@suse.com>

Signed-off-by: David Sterba <dsterba@suse.com>

Signed-off-by: David Sterba <dsterba@suse.com>

This function prints an informative message and then continues
dev-replace. The message contains a progress percentage which is read
from the status. The status is allocated dynamically, about 2600 bytes,
just to read the single value. That's an overkill. We'll use the new
helper and drop the allocation.
Signed-off-by: David Sterba <dsterba@suse.com>

We'll want to read the percentage value from dev_replace elsewhere, move
the logic to a separate helper.
Signed-off-by: David Sterba <dsterba@suse.com>

All sorts of readahead errors are not considered fatal. We can continue
defragmentation without it, with some potential slow down, which will
last only for the current inode.
Signed-off-by: David Sterba <dsterba@suse.com>

We can safely use GFP_KERNEL, the function is called from two contexts:

- ioctl handler, called directly, no locks taken
- cleaner thread, running all queued defrag work, outside of any locks
Signed-off-by: David Sterba <dsterba@suse.com>

We don't need to restrict the allocation flags in btrfs_mount or
_remount. No big filesystem locks are held (possibly s_umount but that
does no count here).
Signed-off-by: David Sterba <dsterba@suse.com>